We have experienced several hard freezes recently in the Red River Valley and hardy plants are settling in for the long winter months. Whether you have added to your landscape recently or have a well-established space, preparing them for winter can aid in a successful spring landscape.
Mulching around trees, perennials and in landscape beds benefits landscape plants in many ways, let’s talk about why mulch is a helpful yard and garden tool. Mulch, by definition, is a protective layer of material that is spread over soil to conserve moisture, suppress weeds and regulate soil temperature. Mulch materials can be organic matter, such as shredded leaves or bark and inorganic materials like rock and landscape fabric.
Shredded bark or wood chips are the most common types of landscape mulch; these are best for landscape beds and around trees. Straw and hay are a common mulch used in vegetable gardens (make sure you are using weed free straw or hay). Grass clippings can also be used in vegetable gardens but make sure to check the source of the clippings and avoid using them if any herbicide was recently used. Stone or smaller rock is common in landscape settings too and lasts for a long time. However, rocks can be very hot during the summer months, causing heat stress in sensitive landscape plants. Large stones can be heavy and may cause soil compaction issues for plants that have roots closer to the surface. A Landscape barrier material is often placed under rock or wood mulch as a weed barrier. Landscape fabric is generally permeable (though there are some that contain plastic elements), letting water and oxygen through and break down over time. Landscape plastic is effective for blocking unwanted plant growth but can cause issues with dry or wet soil because it does not let water pass through it. Plastic barriers are best for pathways or other areas not supporting plants. Landscape barriers are not required for a successful landscape and in some cases can inhibit the ability for insects that burrow into the soil for lifecycle completion or overwintering.
The uses for mulch vary based on landscape plants and goals but are great uses for keeping mowers away from young tree trunks, reducing weed pressure and providing soil and root protection. Moisture retention and soil temperature moderation are important for
healthy root development as well as insulation during the winter months. Organic mulches break down over time, adding nutrients back into the soil, and need to be refreshed every few years. In most landscapes plants eventually grow large enough that they contribute to
weed suppression, moisture and temperature regulation and mulches may not be necessary anymore. However, mulching around trees can continue for many years after planting and can be a continued practice to keep mowers and weed whackers away from the base trees. For more information on choosing mulches check out this article from Penn State Extension https://extension.psu.edu/mulch-a-survey-of-available-options.
Which plants need mulch? Zone hardy plants should be able to withstand the localclimate and overwinter without extra help. However, in years of drought and extreme temperatures (summer and winter) mulch can be a buffer between these factors and plant roots. If borderline hardy plants are being grown (zone 5 and greater), then mulch or otherprotection methods may be necessary.
In any case, make sure all trees, shrubs and perennials are well watered going into the winter months. Newly planted landscape plants should be in the ground 4-6 weeks before the ground freezes. To learn more about landscape design and plant selection visit
https://extension.umn.edu/lawns-and-landscapes/landscape-design.
For questions about this article or local assistance, please contact Clay County Extension Educator Jill Patrie at [email protected] or 218-299-7338.